(Topic ID: 298074)

Are these jumpers on a WPC Power Driver Board legit?

By rockwell

2 years ago


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#1 2 years ago

I have an issue with my (new to me) WCS94 where no flashers work. I began exploring that, and was examining the bridge rectifier and cap in that circuit. Cap looks original. BR4 looks like it had been replaced, and there are jumpers on the back. I've not worked on a WPC PDB before, so I'm not sure if these are appropriate, or perhaps part of the issue. Anyone have thoughts on if these look legit or not? Thanks!

For reference, the jumpers connect:

BR4 Phase -> J105-5
BR4 Neutral -> J105-4
BR4 Neg -> C11 cap (Neg)

PXL_20210805_024454447 (resized).jpgPXL_20210805_024454447 (resized).jpg
PXL_20210805_024536228 (resized).jpgPXL_20210805_024536228 (resized).jpg

#2 2 years ago

From Williams ? NO.

Added on to cover a crappy repair. Lost through hole continuity or something. Not sure if it works or not.

LTG : )

#3 2 years ago
Quoted from LTG:

From Williams ? NO.
Added on to cover a crappy repair. Lost through hole continuity or something. Not sure if it works or not.
LTG : )

Yeah, that was my initial guess. Perhaps a solder pad lifted off and they were trying to remedy? Kinda hard to see without desoldering the globs. The jumpers to the J105 especially confuse me since J105 is unused (and the J104 pins that correspond are unused pins).

If it is a matter of lifted pads/no continuity, is there a more appropriate recommended fix?

PXL_20210805_034202064 (resized).jpgPXL_20210805_034202064 (resized).jpg
PXL_20210805_034138156 (resized).jpgPXL_20210805_034138156 (resized).jpg

#4 2 years ago

Yikes ugly

#5 2 years ago

My whitewater was even worse than that. Jumper wires were left in place. Ugly, but it worked.

Rob

#6 2 years ago
Quoted from rockwell:

is there a more appropriate recommended fix?

Figure out what is wrong. Follow traces on top of the board and below. Try and figure out if you lost continuity across or through the board. Or if you have other problems to deal with.

LTG : )

#7 2 years ago

Have you got 20V at TP7?
Jumpers ugly but are connected to correct place if tracks were damaged in previous repair. See attached diagram.

Wpc89Snippet1 (resized).JPGWpc89Snippet1 (resized).JPG
#8 2 years ago
Quoted from c_mario:

Have you got 20V at TP7?
[quoted image]

I am getting 20v at the test point, yes.

#9 2 years ago

Then do you get it at J105 pin 5 and J107 Pins 5 & 6 .
If so then the pins on J125 and J126 are the control pins/drivers. They are grounded under CPU control to flash a lamp.

Wpc89Snippet2 (resized).JPGWpc89Snippet2 (resized).JPG
#10 2 years ago

What about a broken wire here.

Wpc89Snippet3 (resized).JPGWpc89Snippet3 (resized).JPG
#11 2 years ago
Quoted from c_mario:

Then do you get it at J105 pin 5 and J107 Pins 5 & 6 .[quoted image]

Quoted from c_mario:

What about a broken wire here.[quoted image]

I will check these things today and report back. Thanks for the direction.

#12 2 years ago

It was something to help beef up the tiny traces from bridge to capacitor. Also as mentioned, when the thru holes get taken. I believe Clay at PinRepair brought these to light if I recall. I could be wrong though...

#13 2 years ago
Quoted from chad:

It was something to help beef up the tiny traces from bridge to capacitor. Also as mentioned, when the thru holes get taken. I believe Clay at PinRepair brought these to light if I recall. I could be wrong though...

I'll look into it more. I haven't found anything in reference to this jumper mod so far.

#14 2 years ago

Here is a list of the jumpers.

These jumper mods are pulled from the old pinball repair site that was taken down years ago, Hope they help.

WPC and WPC-S Driver Board Jumpers:
For reference, the driver board is positioned with the solder side showing, and connector J104 at the "top". All jumpers added to the solder side of the driver board.
BR2 to C5: two jumpers. Jumper the positive lead of bridge BR2 to the positive lead of C5. Repeat for the negative leads also.
BR1: ONE jumper. Jumper the AC lead of BR1 (just below the positive lead) to connector J101 pin 7.
C6/C7: jumper the two positive leads of capacitors C6 and C7 together (this also jumpers also helps BR1).
C6: Add another jumper from the positive lead of C6 to TP8 (Test Point 8, 18 volt DC). Note this jumper is not shown in the picture below.
BR3: three jumpers. Jumper the lower AC lead of BR3 (just below the positive lead) to connector J104 pin 1. Jumper the other upper AC lead (to the left of the positive lead) to connector J104 pin 2. Jumper the positive lead of BR3 to the large solenoid fuse trace about 2" below the bridge (see picture below).
BR4: three jumpers: Jumper the negative lead of BR4 to the negative lead of C11. Jumper the AC lead of BR4 (just above the negative lead) to connector J102 pin 1. Jumper the other lower AC lead of BR4 (just below the positive lead) to connector J104 pin 4.
BR5 to C30: two jumpers: Jumper the positive lead of BR5 to the positive lead of C30. Repeat for the negative leads also.

All the above jumpers have been installed. The most important jumper
is the one from BR2 to C5 (the gray wires). Note the "+" (offset leg)
of the bridge goes to the "+" lead of the associated capacitor. The
"-" lead of the bridge is diagonal to the offset "+" lead. Shown is a
WPC and WPC-S style driver board.

#15 2 years ago
Quoted from chad:

BR4: three jumpers: Jumper the negative lead of BR4 to the negative lead of C11. Jumper the AC lead of BR4 (just above the negative lead) to connector J102 pin 1. Jumper the other lower AC lead of BR4 (just below the positive lead) to connector J104 pin 4.

Thanks a lot for that info! Appreciate it.

Looks like the jumpers on my board are attempting to do this, though it looks like the upper/phase wire is going to the wrong place (should be J102-1 but is actually connected to J105-5). I will change that and see if it yields any different results. I will also swap the wire going to J105-4 to J104-4, even though it looks like they are connected.

#16 2 years ago

c_mario I checked for broken wired where you mentioned, an all looks good. I have continuity and in fact I repinned those connectors (at the plug not the board).

As far as voltages go, I am getting...

J105-5: 0.62VDC
J107-5: 1.53VDC
J107-6: 1.52VDC

Should those all be 20v? Looks like J107-6 should be, at least.

I also re-jumpered the wires as per chad , but so far same results...no flashers.

Also, fuse 111 is good.

#17 2 years ago
Quoted from rockwell:

I have an issue with my (new to me) WCS94 where no flashers work. I began exploring that, and was examining the bridge rectifier and cap in that circuit. Cap looks original. BR4 looks like it had been replaced, and there are jumpers on the back. I've not worked on a WPC PDB before, so I'm not sure if these are appropriate, or perhaps part of the issue. Anyone have thoughts on if these look legit or not? Thanks!

WARNING! *FREE SPEECH COMING DONT READ IF EASILY OFFENDED*

LTG covered this already but this is what happens when someone is overconfident in their abilities to repair circuit boards fails miserably and then has to hack the board to get it to work. The Bridge rectifier on these boards is likely the simplest thing to replace on this entire board. Hopefully whoever did this learned that they are not competent to repair these boards and stopped at this one...but I doubt it.

#18 2 years ago
Quoted from Pin_Guy:

Hopefully whoever did this learned that they are not competent to repair these boards and stopped at this one...but I doubt it.

I just fixed two WPC-89 power boards.

For one of them the "repair technician" had replaced BR1, BR2, BR4, C5 and C11. BR2 had a pulled pad and through hole on one of the AC inputs. BR4 had a pulled through hole. Nearby R194 was cooked. Obviously cooked (as in white dust in the center of the body). I don't know how you replace BR4 without seeing the obviously cooked nearby resistor. I assume the resistor cooked because someone erroneously plugged J106 into (most likely) J124 or J128. This is unfortunately more common than you think. 50V (closer to 75V actually) through that 2k resistor for the LED will definitely cook it over time. Dissipated power >= ~2W through a 0.25W resistor.

The worst part about this "repair" was the work was done and was not verified or tested. The board didn't even generate +5V due to the through hole damage to BR2 which affected the trace between BR2 and C5. Such a repair costs more than a normal repair because the damage has to be repaired on top of the original problem that was supposed to have been repaired. I advised the owner of the board to never use that "repair technician" again. The sorriest aspect of the whole thing is exactly described above. The "repair technician" will never see their mistake so they will continue to make it.

Sorry. That was off topic.

Quoted from rockwell:

I am getting 20v at the test point, yes.

Quoted from rockwell:

As far as voltages go, I am getting...
J105-5: 0.62VDC
J107-5: 1.53VDC
J107-6: 1.52VDC
Should those all be 20v? Looks like J107-6 should be, at least.

J105 is AC. You should not be measuring DC at this header. J107-5,6 are continuous and should read +20VDC.

If you have +20V at the TP but your above measurements at J107-5,6 then you have a problem on your board. Measure continuity between the points to find the break.

flasher_power.jpgflasher_power.jpg

Green has voltage. Red does not. There has to be a break between the two points. Check continuity with an eye at the orange points. You can also post better images of the front and back of your board as it might be visually evident to someone with good eyes.

#19 2 years ago

Thanks for the detailed thoughts and visual aids DumbAss .

I re-measured AC voltage at J105 and got 8.4VAC.

I checked the continuity of the resistor you noted in the above schematic. I can confirm continuity from J107 to Resistor, across the resistor, and from resistor to TP7.

I measured the resistor value itself, which read 0.2 ohm (should be 12). So that seems like it will need replacing. Not sure if that is the source of our no-flashers issue?

Here are some better images. Happy to get some detail shots if needed.

PXL_20210806_023149139 (resized).jpgPXL_20210806_023149139 (resized).jpg
PXL_20210806_023216025 (resized).jpgPXL_20210806_023216025 (resized).jpg

#20 2 years ago
Quoted from rockwell:

I re-measured AC voltage at J105 and got 8.4VAC.

That seems low. I believe it's nominally 20VAC producing 28VDC. 8.4VAC produces 12VDC and that's not what you stated you measured (20VDC at TP7).

Quoted from rockwell:

I measured the resistor value itself, which read 0.2 ohm (should be 12). So that seems like it will need replacing. Not sure if that is the source of our no-flashers issue?

The value of this resistor is R12 or 0.12 Ohms. It is NOT 12 Ohms. If your DMM shows 0.2 Ohms that's fine. There is no need to replace this (relatively hard to find) resistor.

Quoted from rockwell:

I checked the continuity of the resistor you noted in the above schematic. I can confirm continuity from J107 to Resistor, across the resistor, and from resistor to TP7.

Test continuity at all the points with a red arrow. They should all be "continuous" with each other. Continuity here is defined by what I expect your DMM will think is continuity. That is a value < 5 Ohm. What you report with continuity and your readings does not make much sense to me. It might make sense to someone else who has more knowledge or experience than me.

20vdc.jpg20vdc.jpg

If you have continuity at all points to all other points with a red arrow then I hate to say this but I think you're measuring incorrectly. Clip the black lead to either the GND test point or ground braid. Set your DMM to DC voltage (V with a horizontal (straight) line above it). Place the red lead at the test point (TP7) and measure. It should read 28VDC. Place the red lead at J107-5 or J107-6 and measure. Same deal.

Report your findings.

#21 2 years ago
Quoted from DumbAss:

That seems low. I believe it's nominally 20VAC producing 28VDC. 8.4VAC produces 12VDC and that's not what you stated you measured (20VDC at TP7).

Sure thing. My measuring procedure is correct, but I think I may have been measuring the wrong pin. I measured j104-4 which read 8.4VAC. Measuring pins 1 and 2, and there I get 26 and 28 VAC.

Quoted from DumbAss:

Test continuity at all the points with a red arrow. They should all be "continuous" with each other.

Confirmed all points continuous.

Quoted from DumbAss:

If you have continuity at all points to all other points with a red arrow then I hate to say this but I think you're measuring incorrectly. Clip the black lead to either the GND test point or ground braid. Set your DMM to DC voltage (V with a horizontal (straight) line above it). Place the red lead at the test point (TP7) and measure. It should read 28VDC. Place the red lead at J107-5 or J107-6 and measure. Same deal.

I redid the measurements, and am getting about 21.5 VDC at both TP7 and on J107-5/6.

TP7TP7
J107J107

#22 2 years ago
Quoted from rockwell:

Measuring pins 1 and 2, and there I get 26 and 28 VAC.

That seems a bit high. It's been a while since I've measured transformer secondaries so don't rely on that as fact.

To be sure you would have to measure the direct output of the transformer. Take the board connections out of the picture. You can take the measurements between J102-1,2 and J102-3,4.

Quoted from rockwell:

Confirmed all points continuous.

I redid the measurements, and am getting about 21.5 VDC at both TP7 and on J107-5/6.

If you measure 26VAC but are getting 21.5 VDC then you have some loss somewhere. Measure the AC ripple. C11 might not be working correctly.

If you're only interested in why the flashers don't work then the problem may be

  • Broken connection at the connector for J107-5,6.
  • Broken wire somewhere between the header and the first or subsequent flasher socket in the playfield.
  • Broken drive transistor on the power board.
  • Broken ground connection for drive transistor(s) on the power board.
  • Digital logic or pre-drive transistor on the power board.

Start with the easy stuff. Check for power at the flasher sockets in the playfield.

#23 2 years ago

If you momentarily ground pin 1 J125 the black brown wire does the left Goal Cage Top flasher flash.
I mean do this on the plug with it disconnected from the board, not the pins on the board.
U3 and U2 LS3743 IC's trigger the flashers but I find it odd that no flashers work if you are getting 20Vdc at the J107 Pins 5/6.
Perhaps there is no 5v dc at pin 20 of the U3 and U2 ic's.

#24 2 years ago
Quoted from DumbAss:

If you're only interested in why the flashers don't work then the problem may be

Broken connection at the connector for J107-5,6.
Broken wire somewhere between the header and the first or subsequent flasher socket in the playfield.
Broken drive transistor on the power board.
Broken ground connection for drive transistor(s) on the power board.
Digital logic or pre-drive transistor on the power board.

Start with the easy stuff. Check for power at the flasher sockets in the playfield.

I will give these things a look this afternoon when I am back home. Thanks again for the help. I'll report my findings.

Quoted from c_mario:

If you momentarily ground pin 1 J125 the black brown wire does the left Goal Cage Top flasher flash.

I tried this quick, no flash. (Shorting the J125-1 pin to the ground braid in the backbox, power on ).

#25 2 years ago

Then what dumbass said
Broken wire somewhere between the header and the first or subsequent flasher socket in the playfield.

#26 2 years ago

Thanks again for directing me to the right spot. After some digging, I did find one hidden 22 gauge unattached red/white wire at the back of the playfield. It was tied into that harness, but I removed it for this image:

PXL_20210806_192535233 (resized).jpgPXL_20210806_192535233 (resized).jpg

I inspected other 22 gauge red/white wires in the area but they all seem to be attached/intact. I'm guessing it should probably be attached to that lamp that has the 18 gauge red/white wire in the image, so I'll give that a closer look and see if it looks like it broke off of there.

Getting closer. Hopefully.

#27 2 years ago

Interesting. Connected loose wire to lug with the 18awg wire from the header (J107-6), and still nothing in flasher test.

Confirmed continuity from header plug to that first lamp (18awg wire), and continuity from that lamp to the next (22awg wire). Also confirmed I have 20.5VDc at J107-6.

Maybe something else is broke further along the chain. Will explore.

#28 2 years ago

Even though nothing was working in flash test, turned on a game, and...most of the flashers are working. Here is a quick video:

https://photos.app.goo.gl/bXTUdCztyhimq4Pu9

The flash lamp at the rear left corner and the lamp near the left ramp entrance are not working, so might have bad bulb there or something else might be broken. I can't quite see the corner one, but looks like the other dark bulb has its wires connected proper.

#29 2 years ago
Quoted from LTG:

Figure out what is wrong. Follow traces on top of the board and below. Try and figure out if you lost continuity across or through the board. Or if you have other problems to deal with.
LTG : )

I mean....

It sure looks to me that at the VERY LEAST the top of the the through holes on all three of those legs outside the trace on the underside are destroyed, if not the entire via itself. Those wires sure appear to be soldered directly to the component leg, and poorly at that.

The good repair for this is an expensive eyelet repair kit to put a new plated through hole in there. With no trace on the backside, a solder stitch (which would be the cheap home tech fix) isn't really doable.

#30 2 years ago
Quoted from rockwell:

Even though nothing was working in flash test, turned on a game, and...most of the flashers are working.

Did/do you hold in the coin door interlock while running the flasher test?

#31 2 years ago
Quoted from Frax:

Did/do you hold in the coin door interlock while running the flasher test?

I did not, no.

And for sure, at least one of those legs of the BR4 is directly soldered to a wire, no more eyelet. I tried to clean up those solder joints and confirmed they were basically all either missing or half-missing.

#32 2 years ago

Give it a shot. Bet you the flashers fire normally in test that way if they're working in a normal play setting.

#33 2 years ago
Quoted from Frax:

Give it a shot. Bet you the flashers fire normally in test that way if they're working in a normal play setting.

Cool, I will give that a shot. Appreciate the tip.

*****

I'm not sure, but another issue I am troubleshooting may be related. I started a new post about it, but basically I am experiencing pretty weak coils across the whole game. I'm hoping that the questionable repairs made to this board aren't the culprit

https://pinside.com/pinball/forum/topic/need-help-troubleshooting-weak-coils#post-6430878

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